Bookmaker Margin Calculator: Compare Commissions
Calculate the margin and commission taken by the bookmaker on each market
What is the bookmaker margin?
The bookmaker margin (or overround) is the commission that the bookmaker takes on each market. It represents the difference between the sum of implied probabilities from the odds and 100%. The higher the margin, the more money the bookmaker keeps and the less bettors receive in return.
How does the margin affect bettors?
A high margin means the odds are less competitive. In the long run, you lose more money with high-margin bookmakers. By comparing margins across different sites, you can identify those that offer the best conditions for your bets.
Typical margins by bookmaker type
- Exchanges (Betfair, etc.): Margin generally below 5% — bettors compete against each other, the operator takes a small commission
- Competitive traditional bookmakers : Margin between 5% and 8% on popular markets (football, tennis)
- High-margin bookmakers: Margin above 8% — avoid if you want competitive odds
Formula: Margin = (1/odds1 + 1/odds2 + 1/odds3 − 1) × 100 | Payout Rate = 100 − Margin
How This Tool Works
The Bookmaker Margin Calculator reveals how much commission a bookmaker takes on each market. By entering the odds for all outcomes, you can see the overround (margin) and compare bookmaker competitiveness. Lower margins mean better odds and more value for you.
How to Use
- 1Enter the odds for each outcome in a market
- 2The calculator shows the total implied probability and the bookmaker's margin
- 3A margin of 2-3% is excellent; 5-6% is average; 8%+ is poor
- 4Compare the same market across bookmakers to find the lowest margin
Pro Tips
- Pinnacle consistently offers the lowest margins (1.5-3%)
- Regulated markets often have higher margins due to operator taxes
- Main markets (match winner) usually have lower margins than exotic markets (correct score)
- Pre-match margins are typically lower than live betting margins